Your Brain on Chocolate

There has been a great deal of news about the benefits of dark chocolate and cocoa powder, which contain large quantities of antioxidant chemicals called flavan-3-ols (flavanols), aromatic chemicals also found in apples, grapes, cherries, and tea (Nehlig, 2013). Flavanols in chocolate are mostly in the form of catechin and epicatechin, which are converted into glucunorides. These glucunorides latch on to all sorts of molecules in the body to make them more water-soluble so they can travel around more freely, making it easier to take good molecules, like hormones, where they’re needed, and take bad molecules, like pollutants, out of the body. These flavanols can also enter the brain, helping with perfusion (blood flow), neurogenesis (building new brain cells), and angiogenesis (building new blood vessels), and preventing damage from oxygen free-radicals, those nasty molecules that run around the body with their extra electron pairs oxidizing and ruining everything in sight. 

 

Cocoa beans also have high concentrations of theobromine, a methylxanthine similar to caffeine but with less effects as a stimulant to the central nervous system. Theobromine acts as a vasodilator (dilating blood vessels), which decreases blood pressure, and may be better than codeine in suppressing vagus nerve activity and reducing coughing fits. Theobromine is toxic at high doses, but the amounts found even in dark or baker’s chocolate are low enough that very large quantities (say, about 2 kilograms) would have to be consumed to be toxic. However, feeding chocolate, especially dark chocolate, to dogs can be fatal (theobromine is even more toxic to cats, but fortunately cats don’t have a sweet tooth).

 

What Do the Studies Say?

 

In a double-blind, placebo-controlled study (Crews et al., 2008), about 50 healthy older adults were given a daily dose of a 37-gram chocolate bar and an 8-ounce cup of cocoa for 6 weeks, and 50 adults were given “similar placebo products” (not surprisingly, most of them knew the difference). The authors found no significant differences in either neuropsychological or cardiovascular functioning, although toward the end of the study the heart rates of the chocolate group were a bit higher, probably because they were upset that they would no longer get free chocolate.

 

In a more recent double-blind, placebo-controlled study (Lamport et al., 2015), a group of 18 healthy older adults were given either low- or high-flavanol cocoa to see if it helped their memory and learning. Using functional magnetic resonance imaging (fMRI), they found that those in the high-flavanol group showed significantly greater increases in blood perfusion in the cerebrum of the brain, which may benefit cognitive performance.

  

While high-flavanol cocoa may get the blood in your brain to flow faster, what about performance on cognitive testing? A flavanol study that same year (Mastroiacovo et al., 2015) used a larger group of 90 older adults, who were given either high-, medium-, and low-flavanol cocoa drinks. Those in the both the high- and medium-flavanol groups scored better on a connect-the-dots tests and verbal fluency tasks. More important, there was significantly greater improvement in insulin resistance, blood pressure, and the metabolic breakdown of lipids (fatty acids).

 

News Flash! Chocolate Makes You Smarter

 

One study about the cognitive benefits of chocolate (Crichton, 2016) made the news and has been bouncing around the Internet rather dramatically. The study examined self-reported chocolate consumption from a group of 968 individuals aged 23 to 98 years old who have been involved in the Maine-Syracuse Longitudinal Study, a 40-plus year, community-based study of cardiovascular risk factors. The authors found that more frequent chocolate consumption was significantly associated with better performance on a number of cognitive tests. The authors did make it clear this was just a correlation and did not conclude that chocolate causes improved cognitive performance, but of course that is what has been reported by news outlets and internet blogs since the study came out. 

  

Of interest was the author’s finding that those who ate more chocolate had lower levels of hypertension and diabetes, and also drank significantly less alcohol. They did not conclude, of course, that eating lots of chocolate prevents diabetes, high blood pressure, and alcoholism. Rather, they did note that people in higher socioeconomic levels (who have lower incidences of hypertension, diabetes, and alcohol consumption, and who were also better educated) perhaps has more money available to purchase those more expensive, high-flavanol dark chocolate bars.

 

What You Should Do

  

The most important benefit of an occasional dark chocolate is the happiness and joy one feels eating such a treat, because positive emotions are essential for a health body and a healthy mind. So don’t feel guilty for eating a small (preferably dark) chocolate treat on a weekly basis, and those with diabetes can also benefit from sugar-free dark chocolates. And, for heaven’s sake, don’t feed chocolate to the dog!

  

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References

 

Crichton, G. E., Elias, M. F., & Alkerwi, A. (2016). Chocolate intake is associated with better cognitive function: The Maine-Syracuse Longitudinal Study. Appetite, 100, 126-132.

 

Crews, W. D. Jr., Harrison, D. W., & Wright, J. W. (2008). A double-blind, placebo-controlled, randomized trial of the effects of dark chocolate and cocoa on variables associated with neuropsychological functioning and cardiovascular health: Clinical findings from a sample of healthy, cognitively intact older adults. American Journal of Clinical Nutrition, 87, 872-880.

 

Lamport, D. J, Pal, D., Moutsiana, C., Field, D. T., Williams, C. M., Spencer, J. P., & Butler L. T. (2015). The effect of flavanol-rich cocoa on cerebral perfusion in healthy older adults during conscious resting state: a placebo controlled, crossover, acute trial. Psychopharmacology, 323, 3227-3234.

 

Mastroiacovo, D., Kwik-Uribe, C., Grassi, D., Necozione, S., Raffaele, A., Pistacchio, L., et al. (2015). Cocoa flavanol consumption improves cognitive function, blood pressure control, and metabolic profile in elderly subjects: The Cocoa, Cognition, and Aging (CoCoA) Study--a randomized controlled trial. American Journal of Clinical Nutrition, 101, 538-548.

 

Nehlig, A. (2013). The neuroprotective effects of cocoa flavanol and its influence on cognitive performance. British Journal of Clinical Pharmacology, 75, 716-727.

David L. Raffle, PhD